Influence of organic soil amendments on Verticillium dahliae and on the microbial composition of the strawberry rhizosphere

A technique was developed for assessing the saprophytic activity of Verticillium dahliae, using a strawberry root extract medium. The germination of conidia and microsclerotia, and mycelial growth in soil, was inhibited by the addition of chitin, laminarin, wheat straw and oven-dried green clover as soil amendments. A significant decrease in the number of viable propagules of the pathogen counted from soil, and in disease severity, was obtained with chitin and laminarin. More bacteria and actinomycetes were recorded from the rhizosphere of plants grown in chitin-amended soil than from those in natural soil.     

Species-specific sperm adhesion in sea urchins. A quantitative investigation of bindin- mediated egg agglutination

Bindin, a protein component of the acrosomal vesicle of sea urchin sperm, has been isolated from Arbacia punctulata and strongylocentrous purpuratus. Using this isolated bindin, we have devised a quantitative assay for bindin-mediated egg agglutination and compared the agglutination of bindin eggs from A. puntulata and S. purpuratus. Bindin- mediated agglutination is species –specific in both species, although a measurable degree of heterotypic interaction is observed. Homotypic bindin-egg interactions differ significantly from heterotypic interactions both in the extent of agglutination and the size of the resulting aggregates. We also provide direct evidence that bindin particles agglutinate eggs by adhering to the surfaces of adjacent eggs. Although the A. punctulata bindin preparation displays the same functional properties and consists of one major polypeptide of the same apparent molecular weight as S. purpuratus bindin, its morphology is very different. Unlike the spherical aggregates observed with S. purpuratus bindin, A punctulata bindin exists as lamellar vesicles and binds significant amounts of phospholipids and Triton X-100, suggesting that it may be tightly associated with the acrosomal membrane. Having defined a number of the basic parameters of bindin-mediated agglutination, we examined the effect of a number of saccharides and glycopeptides on bindin-mediated egg agglutination. Carbohydrate-containing components derived from the egg cell surface by proteolysis were found to inhibit bindin-mediated egg agglutination at low concentrations, but this inhibition is not species specific.     

COLD-TOLERANT FERMENTATIVE GRAM-NEGATIVE ORGANISMS FROM MEAT AND OTHER SOURCES

SUMMARY: From various chilled meats, twenty-eight strains of coli-aerogenes bacteria and one Aeromonas were isolated which grew well at +1±5° and some at −1±5°. The optimum growth temperature for most of these strains was nearer 37° than 30°. Nine strains (including the Aeromonas ) fermented lactose rapidly, the remainder slowly or not at all. All the strains which fermented lactose rapidly with the production of gas gave positive presumptive coli-aerogenes tests in MacConkey's broth at 30°, but only five were positive at 37°; none was positive at 44°. Because such organisms can attain populations of millions/cm², they could confuse the interpretation of presumptive coli-aerogenes tests made on chilled meat.     

Lectin histochemistry for detecting cadmium-induced changes in the glycosylation pattern of rat placenta

Cadmium (Cd) is an industrial and environmental pollutant that produces toxic effects on gametogenesis, pre- and post-implantation embryos, and the placenta. Because the effects of acute Cd intoxication on the placenta are not well understood, we investigated changes in its glycosylated components in Cd treated dams at days 4, 7, 10 and 15 of gestation using lectin histochemistry. CdCl₂ was administered to pregnant rats; control animals received sterile normal saline. Placentas were processed for DBA, Con A, SBA, PNA, UEA-I, RCA-I and WGA lectin histochemistry to evaluate changes in the carbohydrate pattern of the placenta that might modify cell interactions and contribute to embryonic alterations. Lectin binding was analyzed in the yolk sac; trophoblast giant cells; trophoblast I, II and III; spongiotrophoblast cells and endovascular trophoblast cells in the chorioallantoic placenta. Our lectin binding patterns showed that Cd caused alteration of SBA and DBA labeling of trophoblast-derived cells, which suggested increased expressions of α and β GalNAc. Cd also caused decreased UEA-1 binding affinity, which indicated fewer α-L-Fuc residues in placentas of Cd treated dams. The nonreactivity in trophoblast I of the control placentas incubated with Con-A contrasted with the labeling in placentas of experimental dams, which indicated increased expression of terminal α-D-Man, and α-D-Glc residues. We found that Cd altered the reactivity of placenta to several lectins, which indicated modification of the glycotype presented by the fetal component of the placenta. We report that Cd exerts a deleterious effect on the glycosylation pattern of the placenta.     

Amplified centrosomes may underlie aggressive disease course in pancreatic ductal adenocarcinoma

Centrosome amplification (CA), the presence of centrosomes that are abnormally numerous or enlarged, is a well-established driver of tumor initiation and progression associated with poor prognosis across a diversity of malignancies. Pancreatic ductal adenocarcinoma (PDAC) carries one of the most dismal prognoses of all cancer types. A majority of these tumors are characterized by numerical and structural centrosomal aberrations, but it is unknown how CA contributes to the disease and patient outcomes. In this study, we sought to determine whether CA was associated with worse clinical outcomes, poor prognostic indicators, markers of epithelial-mesenchymal transition (EMT), and ethnicity in PDAC. We also evaluated whether CA could precipitate more aggressive phenotypes in a panel of cultured PDAC cell lines. Using publicly available microarray data, we found that increased expression of genes whose dysregulation promotes CA was associated with worse overall survival and increased EMT marker expression in PDAC. Quantitative analysis of centrosomal profiles in PDAC cell lines and tissue sections uncovered varying levels of CA, and the expression of CA markers was associated with the expression of EMT markers. We induced CA in PDAC cells and found that CA empowered them with enhanced invasive and migratory capabilities. In addition, we discovered that PDACs from African American (AA) patients exhibited a greater extent of both numerical and structural CA than PDACs from European American (EA) patients. Taken together, these findings suggest that CA may fuel a more aggressive disease course in PDAC patients.     

Effects of benthivorous bream (Abramis brama) and carp (Cyprinus carpio) on sediment resuspension and concentrations of nutrients and chlorophyll a

1. The effect of benthivorous bream and carp on sediment resuspension and the concentrations of nutrients and chlorophyll a were studied in sixteen experimental ponds (mean depth 1m, mean area 0.1 ha, sandy clay/clay sediment), stocked with bream or carp at densities varying from 0 to 500 kg ha^?1. Planktivorous perch (Perca fluviatilis L.) were added to some ponds to suppress zooplankton. 2. Suspended sediment concentrations increased linearly with biomass of benthivorous fish. Bream caused an increase of 46 g sediment m^?2 day^?1 per 100kg bream ha^?1 and a reduction of 0.38m^?1 in reciprocal Secchi disc depth, corresponding to an increase in the extinction coefficient of 0.34m^?1. 3. No relationship was found between size of fish and amount of resuspension, but the effect of bream was twice as great as that of carp. Benthivorous feeding was reduced in May because alternative food (zooplankton) was available. 4. Assuming a linear relationship, chlorophyll a level increased by 9.0 μgI^?1, total P by 0.03mgl^?1 and Kjeldahl-N by 0.48mgl^?1 per 100kg bream ha^?1. Silicate, chlorophyll a, total P and total N were all positively correlated with fish biomass, but orthophosphate showed no correlation.